//download.js v3.0, by dandavis; 2008-2014. [CCBY2] see http://danml.com/download.html for tests/usage
// v1 landed a FF+Chrome compat way of downloading strings to local un-named files, upgraded to use a hidden frame and optional mime
// v2 added named files via a[download], msSaveBlob, IE (10+) support, and window.URL support for larger+faster saves than dataURLs
// v3 added dataURL and Blob Input, bind-toggle arity, and legacy dataURL fallback was improved with force-download mime and base64 support

// data can be a string, Blob, File, or dataURL


function download(data, strFileName, strMimeType) {

    var self = window, // this script is only for browsers anyway...
        u    = "application/octet-stream", // this default mime also triggers iframe downloads
        m    = strMimeType || u,
        x    = data,
        D    = document,
        a    = D.createElement("a"),
        z    = function (a) {
            return String(a);
        },


        B    = self.Blob || self.MozBlob || self.WebKitBlob || z,
        BB   = self.MSBlobBuilder || self.WebKitBlobBuilder || self.BlobBuilder,
        fn   = strFileName || "download",
        blob,
        b,
        ua,
        fr;

    //if(typeof B.bind === 'function' ){ B=B.bind(self); }

    if (String(this) === "true") { //reverse arguments, allowing download.bind(true, "text/xml", "export.xml") to act as a callback
        x = [ x, m ];
        m = x[ 0 ];
        x = x[ 1 ];
    }


    //go ahead and download dataURLs right away
    if (String(x).match(/^data\:[\w+\-]+\/[\w+\-]+[,;]/)) {
        return navigator.msSaveBlob ? // IE10 can't do a[download], only Blobs:
            navigator.msSaveBlob(d2b(x), fn) : saver(x); // everyone else can save dataURLs un-processed
    } //end if dataURL passed?

    try {

        blob = x instanceof B ? x : new B([ x ], {
            type: m
        });
    } catch (y) {
        if (BB) {
            b = new BB();
            b.append([ x ]);
            blob = b.getBlob(m); // the blob
        }

    }


    function d2b(u) {
        var p   = u.split(/[:;,]/),
            t   = p[ 1 ],
            dec = p[ 2 ] == "base64" ? atob : decodeURIComponent,
            bin = dec(p.pop()),
            mx  = bin.length,
            i   = 0,
            uia = new Uint8Array(mx);

        for (i ; i < mx ; ++i) uia[ i ] = bin.charCodeAt(i);

        return new B([ uia ], {
            type: t
        });
    }

    function saver(url, winMode) {


        if ('download' in a) { //html5 A[download]
            a.href = url;
            a.setAttribute("download", fn);
            a.innerHTML = "downloading...";
            D.body.appendChild(a);
            setTimeout(function () {
                a.click();
                D.body.removeChild(a);
                if (winMode === true) {
                    setTimeout(function () {
                        self.URL.revokeObjectURL(a.href);
                    }, 250);
                }
            }, 66);
            return true;
        }

        //do iframe dataURL download (old ch+FF):
        var f = D.createElement("iframe");
        D.body.appendChild(f);
        if (!winMode) { // force a mime that will download:
            url = "data:" + url.replace(/^data:([\w\/\-\+]+)/, u);
        }


        f.src = url;
        setTimeout(function () {
            D.body.removeChild(f);
        }, 333);

    } //end saver


    if (navigator.msSaveBlob) { // IE10+ : (has Blob, but not a[download] or URL)
        return navigator.msSaveBlob(blob, fn);
    }

    if (self.URL) { // simple fast and modern way using Blob and URL:
        saver(self.URL.createObjectURL(blob), true);
    } else {
        // handle non-Blob()+non-URL browsers:
        if (typeof blob === "string" || blob.constructor === z) {
            try {
                return saver("data:" + m + ";base64," + self.btoa(blob));
            } catch (y) {
                return saver("data:" + m + "," + encodeURIComponent(blob));
            }
        }

        // Blob but not URL:
        fr        = new FileReader();
        fr.onload = function (e) {
            saver(this.result);
        };
        fr.readAsDataURL(blob);
    }
    return true;
}

/* end download() */

export default download;
